Cisco Cisco Certifications 210-250 Questions & Answers

• Question 311:

  Which one of the following is the first exchange during SSHv1 authentication negotiation?

  A. The server requests a username and password from the user.

  B. The server sends a public key to the client.

  C. The client generates a session key.

  D. The client and server agree upon the encryption algorithm.

  Correct Answer: B

• Question 312:

  Which statement about the Diffie-Hellman Key Agreement is true?

  A. The higher the Diffie-Hellman group number indicates a smaller key size.

  B. The higher the Diffie-Hellman group number indicates a larger key size.

  C. The higher the Diffie-Hellman group number indicates no difference in processing requirements.

  D. The higher the Diffie-Hellman group number indicates a smaller prime number (p).

  Correct Answer: B

• Question 313:

  To provide origin authentication, the sender encrypts the message using an asymmetric encryption algorithm. In this case, the receiver of the message must use what to decrypt the message?

  A. sender's digital signature

  B. sender's shared key

  C. sender's private key

  D. sender's public key

  Correct Answer: D

• Question 314:

  Which one of the following parts of the Diffie-Hellman calculation is an arbitrary item that is agreed upon by both parties before any mathematical calculations?

  A. prime number (p)

  B. secret key (a)

  C. public key (g)

  D. shared key (s)

  Correct Answer: A

• Question 315:

  Which one of the following encryption methodologies allows you to maintain the privacy of an email communication, and ensure the origin of the message using PGP?

  A. Encrypt the message with your public key and send your private key to the destination in a separate email so that the recipients can decrypt your message and know that you sent them the key.

  B. Encrypt the message with your private key, and again with the destination's public key, so that the recipients can decrypt the message with their private key and your public key.

  C. Encrypt the message with your public key, and again with the destination's private key, so that the recipients can decrypt the message with your private key and their public key.

  D. Encrypt the message with the destination's private key so that the recipients can decrypt it with their private key and know they are the only party who generated the private key.

  Correct Answer: B

• Question 316:

  Which one of the following encryption algorithms is the preferred symmetrical algorithm that is intended to replace 3DES?

  A. DES

  B. SHA256

  C. DSA

  D. AES

  E. MD5

  F. RSA

  Correct Answer: D

• Question 317:

  Of the following, in which type of an attack does the attacker try every possible key with the decryption algorithm, knowing that eventually one of the keys will work?

  A. chosen-ciphertext attack

  B. ciphertext-only attack

  C. brute-force attack

  D. birthday attack

  Correct Answer: C

• Question 318:

  Which one of the following options is the block cipher mode that uses an encryption method which has a feedback mechanism where each plaintext block is XORed with the previously encrypted block, and then is encrypted with the DES key?

  A. ECB

  B. DES

  C. CBC

  D. 3DES

  Correct Answer: C

• Question 319:

  Which one of the following statements best describes crypto analysis?

  A. The practice of creating codes to obscure the meaning of plaintext data.

  B. The practice of breaking codes to obtain the fingerprint of encrypted data.

  C. The practice of creating one-way encryption cryptographic algorithms.

  D. The practice of breaking codes to obtain the meaning of encrypted data.

  Correct Answer: D

• Question 320:

  One cryptanalysis method that is used to defeat a multi-step encryption process uses both the original clear text to work forward toward an intermediate value, and the ending cipher text to work backward toward an intermediate value so that the key space that is to be defeated is smaller and more computationally manageable. Which one of the following terms describes this method?

  A. brute-force attack

  B. meet-in-the-middle attack

  C. ciphertext-only attack

  D. birthday attack

  Correct Answer: B